Subject:
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Re: Math/Optics Problem
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Newsgroups:
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lugnet.off-topic.geek
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Date:
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Tue, 14 Aug 2001 15:01:53 GMT
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Viewed:
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116 times
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In lugnet.off-topic.geek, Jacob Sparre Andersen writes:
> > #2 If not, will it at least be constant for the same zoom level?
> No.
>
> > #3 are there any other "missing pieces" to the formula?
> Yes: Focus (I think).
>
> > #4 what is the formula for figuring out the distance between the two
> > objects?
>
> dist. from camera = (fisheye const.)*(actual height)/(photo
> height) + (small obscure camera dependent constant)
Hmm... So both the zoom and the focus affect the fisheye constant? How
exactly does the focus change it? I guess I'm imagining the same actual
image in and out of focus and not seeing actual change in the image's shapes
& relative sizes... which would mean that it *would* be constant for the
same zoom level? Or am I not figuring something right?
> > #5 can I use that same formula to find out how far away from the *camera*
> > the objects are?
>
> Yes, but then you have to figure out the value of the "small
> obscure camera dependent constant" .
Just curious-- does this value indicate the distance that the light has to
travel before hitting the focus point? For example, let's say that there's a
maze of mirrors accounting for 12 feet of light-travel distance between the
light entry point of the camera and the final "focal point". Would this
constant then be somewhere in the vicinity of 12 feet? Or does this have
something to do with the distance apart that the lenses of the camera are
(I.E. zoom level I think?)
If the former (that it's only the light-travel distance within the camera),
then I would assume that for most hand-held-type cameras, you could probably
be accurate to within centimeters, while larger "movie" style cameras, you
could probably be accurate to within a foot or two?
DaveE
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Message has 1 Reply:
 | | Re: Math/Optics Problem
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| David: (...) <activate brain/> Hmmm... Maybe not. The focus is probably rather affecting the "small obscure" supposedly only "camera dependent" supposedly "constant". (...) I think I have to open a camera (or an optics textbook) and have a look. (...) (23 years ago, 14-Aug-01, to lugnet.off-topic.geek)
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Message is in Reply To:
| | Re: Math/Optics Problem
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| David: (...) No. (...) No. (...) Yes: Focus (I think). (...) dist. from camera = (fisheye const.)*(actual height)/(photo height) + (small obscure camera dependent constant) Since you only ask about the relative distance, the "small doesn't matter. (...) (23 years ago, 14-Aug-01, to lugnet.off-topic.geek)
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